Paralyzed tail? Help

This is a discussion on Paralyzed tail? Help within the Tropical Fish Diseases forums, part of the Freshwater Fish and Aquariums category; -->
I've had 8 Mbuna Chichlids in my 55 gal aquarim for about a year. No problems thus far.
Today I notice one of my ...

I've had 8 Mbuna Chichlids in my 55 gal aquarim for about a year. No problems thus far.
Today I notice one of my larger cichlids 3.5-4" long cant use his tail muscles. theres no real physical damage to it and the anal fin with the egg spots appears clamped up tight against the body. he swims with only his pec fins.. Any ideas what this is?? All other fish appear fine. Some are picking on him maybe because he is injured?

6. What fish do you have? How many are in your tank? How big are they? How long have you had them? African Cichlids (MBUNA) 4 yellow labs, 2 Salousi or Demonsi(?) not sure and 1 red zebra and 2 larger albino zebras (I think thats what they are)

7. Were the fish placed under quarantine period (minus the first batch from the point wherein the tank is ready to accommodate the inhabitants)?

12. Foods? New Life Spectrum Pellets
How often are they fed? once a day in the evenings

13. a. Any abnormal signs/symptoms? one of the larger Albino red zebras seems his tail is paralyzed, only swims with pectorial fins and the anal fin with egg spots is clamped tight against his tail. his tail drags on the sand, rocks as he tries and swims about, causing some wear and tear (not sure if this is early fin rot or from abrasion of the sand, rocks and other fish)
b. Appearance of poop?
c. Appearance of gills?

14. a. Have you treated your fish ahead of diagnosis?
b. What meds were used? None